Uncertain electrical signals in hardware create computational problems that no computer can ever solve.
April 23, 2026
Original Paper
Metastability-Containing Turing Machines
arXiv · 2604.17285
The Takeaway
Signal metastability is a physical reality where a circuit stays between a one and a zero. This proof connects that physical glitch to the theoretical limits of logic. The set of all possible outcomes for a machine with these signals is mathematically non-computable. This means that hardware failures are not just annoying bugs but fundamental breaks in the logic of the universe. We can never perfectly predict what a computer will do when its electronics get confused. It sets a hard ceiling on the reliability of any physical computing device.
From the abstract
Metastability is a spurious mode of operation in digital signals, where an electrical signal fails to settle into a stable state within a specified time, leading to uncertainty and potentially failing downstream hardware. A system that computes the closure over all possibilities, given an uncertain input, is called a Metastability-containing system.While prior work has addressed metastability-containing systems in the context of combinational and clocked circuits, state machines, and logic formu